中一數學問題 急

2008-03-20 3:27 am
第一條:6份1(x-4)-4份1(2-x)=2份1

第一條:9=2【16-4(3-x)】

求x值

回答 (4)

2008-03-20 3:42 am
✔ 最佳答案
第一條:
你要首先通分母,咁就易做d ( 姐係乘 4/ 6 / 2 既l.c.m)
呢條最好就乘12因為係最細既l.c.m.
6份1(x-4)-4份1(2-x)=2份1
2(x-4)-3(2-x)=6 (通左之後)
(再拆括號)::
2x-8-6+3x=6 (記得拆第2個括號係負負得正呀!)
5x-14=6
5x=20
x=4

第二條:9=2【16-4(3-x)】
9=2 (16-12+4x)
9=2(4-4x)
9=8-8x
1= -8x
x=負8分一

2008-03-19 19:43:49 補充:
唔好意思我打錯了第2題
9=2(4 + 4x)
9=8 + 8x
1= 8x
x= 8分1
參考: myself
2008-03-20 3:49 am


1/6 . (x-4) - 1/4 . (2-x) = 1/2

x/6 - 4/6 - 1/2 + x/4 = 1/2

x/6 + x/4 = 1/2 + 4/6 + 1/2

5x/12 = 5/3

x = 4




9 = 2〔16-4(3-x)〕

9/2 = 16-4(3-x)

9/2 - 16 = -4(3-x)

-23/2 = -4(3-x)

23/8 = 3-x

23/8 - 3 = -x

23/8 - 24/8 = -x

-1/8 = -x

x = 1/8
2008-03-20 3:46 am
1. (x-4)/6 -(2-x)/4 =1/2
2(x-4) - 3(2-x) = 6
2x-8 -6+3x =6
5x=20
x=4
2. 9=2[16-12+4x]
9=8+8x
x=1/8
2008-03-20 3:38 am
(1/6)(X-4) - (1/4)(2-X) = 1/2
X/6 - 4/6 -2/4 + X/4 = 1/2
5X/12 = 5/3
X = 4



9 = 2[16-4(3-X)]
9 = 2(16-12+4X)
9 = 32-24+8X
1 = 8X
X = 1/8


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